Nerve growth factor (NGF) regulates the development of sympathetic and sensory neurons and other cell types derived from the neural crest. Like other peptide hormones, NGF must physically interact with the cell surface in order to exert its influence on cell development. This surface interaction is mediated by a glycoprotein called nerve growth factor receptor which specifically binds the hormone. A full understanding of subsequent steps is lacking, although there is a variety of speculation in the literature. For example, after binding NGF, the receptor might change its physical properties or its cellular location or might even acquire hormone-dependent enzymatic activity.
Derangement of the development of the neural crest leads to a number of disorders of clinical interest. One derangement of neural crest tissue leads to tumors such as melanomas. Many melanoma cell lines have been shown to bind significantly more NGF than either normal cells or other tumor cells [PNAS 74, 565-569 (1977)]. Genetic methods of identifying the cause of the malignancy, however, have been inconclusive (Nature Vol. 308, pp. 69-62, 1984).
There is a need for a ready diagnostic method to identify when derangement of development of neural crest has occurred.